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MessageEvent: ports property

The ports read-only property of the MessageEvent interface is an array of MessagePort objects representing the ports associated with the channel the message is being sent through (where appropriate, e.g. in channel messaging or when sending a message to a shared worker).

Value

An array of MessagePort objects.

Examples

js

onconnect = (e) => {
  const port = e.ports[0];

  port.addEventListener("message", (e) => {
    const workerResult = `Result: ${e.data[0] * e.data[1]}`;
    port.postMessage(workerResult);
  });

  port.start(); // Required when using addEventListener. Otherwise called implicitly by onmessage setter.
};

Specifications

Specification
HTML Standard
# dom-messageevent-ports-dev

Browser compatibility

Desktop Mobile
Chrome Edge Firefox Internet Explorer Opera Safari WebView Android Chrome Android Firefox for Android Opera Android Safari on IOS Samsung Internet
ports 4 12 3 9 ≤12.1 4 ≤37 18 4 ≤12.1 3.2 1.0

See also

  • ExtendableMessageEvent — similar to this interface but used in interfaces that needs to give more flexibility to authors.

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https://developer.mozilla.org/en-US/docs/Web/API/MessageEvent/ports